1. Field of the Invention
The present invention relates to a reel assembly for a gaming machine and more particularly to a reel assembly for a gaming machine which includes a rotatable reel which carries a strip of symbols and a stepper motor and a lamp device carried by a two piece motor mount assembly configured to enable angular adjustment of the stepper motor with respect to a fixed reel support to facilitate centering of the symbols with the pay lines while the gaming reels remain within the gaming machine
2. Description of the Prior Art
Gaming machines are well known in the art. Such gaming machines are known to include a plurality of reel assemblies. The reel assemblies include a rotatable reel which carries a plastic strip imprinted with symbols. The reel assemblies are rigidly supported in such gaming machines in a side by side relationship such that the axes of rotation of the rotatable reels are essentially horizontal and co-linear. Each rotatable reel is driven independently by a stepper motor, which, in turn, is under the control of stepper motor driver.
The stepper motor driver is a control system for controlling the operation of the stepper motor in response to an external signal. In the context of a gaming machine, the external signal is normally provided by a host game controller. In response to user input, such as a pull of the game lever or depressing a pushbutton to initiate the game, the host game controller generates a random number. As discussed in detail in U.S. Pat. No. 4,711,451, hereby incorporated by reference, each reel is divided up into a predetermined stop positions. These stop positions are stored in memory and normally coincide with the center positions of each of the symbols on the plastic strip carried by the reel. The random numbers generated by the random number generator are then associated with the addresses of the various stop positions for the reel assembly.
As mentioned above, each reel assembly is independently controlled. Thus, the host game controller generates a random number for each reel assembly. Customarily, gaming machines are provided with three (3) reel assemblies. Thus, the host game controller generates a random number for each of three (3) reel assemblies.
An exemplary reel assembly is illustrated in U.S. Pat. No. 5,388,829, hereby incorporated by reference. The gaming machine includes a window for each reel assembly on its front panel. The reel assemblies are mounted in the gaming machine so that one or more symbols on each reel are visible from the outside of the machine through the window. One or more co-linear pay lines are provided adjacent to the windows which indicate the combinations of symbols need to win. Up to four (4) pay lines per machine are known.
Each reel assembly includes a fixed lamp rigidly carried by a frame member. Each reel assembly also carries the stepper motor and the rotatable reel. The reel assemblies and the lamp assemblies are located so as illuminate the symbols behind the windows.
It is important that the symbols on the various side by side reels in the gaming machine be aligned relative to the pay lines. For example, for gaming machines with a single payline, the centerlines of the symbols for each of reels should be essentially co-linear and aligned with the pay line.
Many factors are known to affect the alignment. One factor is known as phase setting. Phase setting relates to the angular position of the symbol positions on power up. More particularly, in some known gaming machines, the reel is mechanically coupled to the stepper motor shaft by way of a cross pin, for example, as illustrated in detail in U.S. Pat. No. 4,410,178.
When the stepper motor driver is initially powered up, it does not know the angular position of the motor shaft or which winding to energize to cause the motor shaft to rotate. As such, the stepper motor is initialized by a procedure known as phase setting. In particular, one winding of the stepper motor is energized for a relatively short period of time, e.g. 1 second. This causes the motor to rotate to and lock in a zero phase position. Once locked in the zero phase position, an encoder counter internal to the stepper motor driver is reset to provide a fixed reference for applying power to each motor phase
It is known that if a load, such as a reel, is applied to the stepper motor during power-up, the zero phase position will be offset slightly. Failure to correct the offset in the zero position can result in the symbols on the reels not properly lining up with the pay lines on the gaming machines and with the symbols on the other reels in the machine. Unfortunately, since gaming machines are configured so that the reel is directly coupled to the stepper motor on power up, the zero position will be offset. As such, manual adjustment is required in the field. In order to correct the offset in the phase setting in the field, the stepper motor housing is physically rotated with respect to the reel assembly frame to align the symbol centerlines with the various pay lines. The procedure for phase setting is described in detail in Standard Operating Procedure SOP-0205-01-N-DEV, Starpoint Electrics Ltd, Pages 1-36, January, 2004, hereby incorporated by reference. In as much as there are normally three (3) reel assemblies per gaming machine, phase setting of each of the reel assemblies in a gaming machine is cumbersome and time consuming.
In order to facilitate fine tuning of the adjustment of the symbol centerlines to the pay lines, various adjustable reel assemblies have been developed which enable the angular position of the stepper motor to be varied relative to a fixed support which carries the reel assembly. Such reel assemblies are disclosed in U.S. Pat. Nos. 5,423,540; 5,688,172; 6,102,396 and European Patent Application Publication No. EP 0 603 230 B1, herein incorporated by reference. Other known adjustable reel assemblies are illustrated in FIGS. 1 and 2. The adjustable reel assembly illustrated in FIG. 1 is manufactured by Starpoint Electrics Ltd. while the one illustrated in FIG. 2 is manufactured by Gamesman Ltd.
The various known reel assemblies as disclosed above all allow angular adjustment of the stepper motor with respect to the reel assembly's fixed support to enable the angular position of the stepper motor to be varied in order to align the symbol centerlines with the pay lines. In order to lock in an adjustment, the adjustment mechanisms all include an adjustment fastener. In order to adjust the angular position of the stepper motor, the adjustment fastener is first unloosened. After the adjustment fastener is unloosened, the stepper motor mount is rotated to the desired position. Once the stepper motor mount is rotated to the desired position, the adjustment screw is re-tightened to lock in the adjustment.
Unfortunately, as shown in FIGS. 1 and 2, the adjustment mechanisms in such reel assemblies are configured in such a manner which requires access to the adjustment screw by a fastener tool along a direction generally parallel to the axis of rotation of reel. Since the reels are disposed in a side by side relationship, the reel assemblies must be removed from the gaming machine in order to loosen the adjustment screw. The stepper motor mount is then rotated and the adjustment screw is re-tightened. After the adjustment screw is unloosened, the stepper motor mount can be rotated outside of the machine and retightened. Because the center line of the symbol must be aligned with the pay line, this method may take several iterations.
Alternatively, the reel assembly can be relocated into the gaming machine with the adjustment screw un-tightened. In the alternative method, the stepper motor mount is rotated to so that the centerline of the symbol on the reel is aligned with the pay line. The reel assembly is then removed to allow re-tightening of the adjustment screw. The reel assembly is then re-installed in the gaming machine. If the adjustment has slipped as a result of the removal and re-installation of the reel assembly, the process must be repeated.
Alignment of the symbol center lines with the pay lines with the various known reel assemblies is relatively cumbersome and time consuming. Thus, there is a need for a reel assembly that facilitates alignment of the symbol center lines with the pay lines.